(a) Technical Field
Exemplary embodiments relate to a resonant converter and a driving method thereof.
(b) Description of the Related Art
A resonant converter is controlled in such a way as to operate in an inductive region in a DC gain characteristic according to an operating frequency. The inductive region is divided into a frequency region below a resonant frequency (hereinafter called a “below resonance”) and a frequency region above the resonant frequency (hereinafter called an “above resonance”) on the basis of the resonant frequency. When the resonant converter operates in the below resonance, non-zero voltage switching may occur.
Although a line voltage supplied to the resonant converter drops out, the resonant converter needs to be able to maintain its output voltage at least during a hold-up time. If the line voltage drops out, however, the input voltage of the resonant converter is reduced and the resonant converter operates in the below resonance. There is a difficulty in regulating the output voltage at least during the hold-up time in a condition in which the input voltage is reduced.